This invention relates to a refrigeration system. More particularly, it relates to a refrigeration system based on a scroll compressor to efficiently provide a flow of air having a reduced temperature.
Refrigeration systems are used in different settings to lower the temperature of a substance below that of its surroundings. They are very commonly used in residential, commercial and industrial plant air conditioning systems where air temperature is controlled. They are also used in specialized situations such as the chemical processing industry for removing heat of chemical reactions, liquefying process gasses and numerous other materials processing steps where air, liquid and solid temperatures must be regulated. Regardless of end use, all refrigeration systems include a compressor, a condenser and an evaporator. All include a refrigerant circulating throughout the system. Different temperature limits and temperature reducing capacities are attained depending on the system components and refrigerant selected.
Environment testing apparatuses in particular are used by many manufacturers in an attempt to predict a product""s durability. A product can be subjected to very controlled temperatures and humidities. In certain instances, a short testing period at preselected conditions will adequately test the product. Oftentimes, the testing is conducted at environmental extremes to hasten the testing process. In effect, a meaningful prediction of a product""s long term durability can be achieved in a relatively short time span.
Environment conditioning apparatuses are also used by manufacturers to subject products to controlled conditions, such as temperature, humidity and pressure. The conditioning is a part of the manufacturing process and is used to impart a certain quality to the product.
Apparatuses built for the environment testing uses discussed above typically include a housing with a test or conditioning chamber for holding the product and a plenum chamber for supplying conditioned air to the test chamber. When reduced temperatures are called for, the conventional refrigeration system of a compressor, condenser and evaporator are connected and placed in communication with the plenum chamber. In such systems, the evaporator is mounted in the test chamber or in an air plenum chamber which is in fluid communication with the test chamber. A cooled refrigerant flowing through coils in the evaporator removes heat from the chamber and thus lowers the chamber temperature. The cooled refrigerant supplied to the evaporator also flows in a closed loop through the compressor and the condenser. The refrigerant is thus continuously cycled in a vapor-compression refrigeration cycle. When an elevated temperature is required, a heater system is in communication with the plenum chamber. Some apparatuses include both refrigeration and heater systems.
Both testing and conditioning apparatuses desirably operate as efficiently as possible. This is particularly important with certain apparatuses designed for use where temperatures substantially below room temperature are required. Efficiency of operation can come from the apparatus itself as well as the refrigerant being used. Various capacity compressors, condensers (air cooled or water cooled) and evaporators of varying designs are available. Refrigerants with different physical characteristics such as boiling points are also known and commercially available. The particular refrigerant selected is typically based on its chemical properties, thermodynamic properties, physical properties, and safety considerations. The refrigerant in effect is matched with the system capacity and the desired test chamber temperature.
Cascade refrigeration systems are known and commonly believed necessary to reach substantially reduced temperatures in the test chamber of a testing and conditioning apparatus. In the cascade refrigeration system, a first stage system including a compressor and condenser cools a refrigerant. This cooled refrigerant is then passed in a heat-exchange relationship with a refrigerant of the second stage. The temperature of this second stage refrigerant is thus lowered before the refrigerant passes through coils in an evaporator. The evaporator is positioned in the test chamber or is in fluid communication with the test chamber. Such basic cascade refrigeration systems have been further modified with bypass circuits to enhance operating efficiencies.
The cascade refrigeration systems are very effective for providing a substantially reduced temperature in the test chamber of an environment testing and conditioning apparatus. However, the need for two compressors in particular substantially increases the unit""s initial cost. The cost of operating and maintaining the system is also noticeably higher. Increased personnel training to properly set-up and run the apparatus also adds to the cost of operation and increases the chance for operator error.
There is an ongoing need for less costly and more efficiently operated refrigeration systems. In accord with this need, there has now been developed a system which is capable of supplying substantially reduced temperatures using only a singular compressor. The system is ideally used as part of a testing and conditioning apparatus to maintain temperature within a test chamber in a narrow reduced temperature range in a cost effective manner.
A refrigeration system includes a singular scroll compressor, a condenser and an evaporator operatively connected together. The refrigeration system is further charged with R410A refrigerant. The scroll compressor and R410A refrigerant synergistically provide very efficient cooling to a reduced temperature of at least about xe2x88x9235 degrees F. The system finds widespread use. In particular, an environment testing and conditioning apparatus which comprises a housing having a test chamber, an air plenum chamber and a mechanics chamber utilizes the refrigeration system. The apparatus is very cost effective because of a need for only the singular scroll compressor and the efficient running of the refrigeration system.